Public Country-by-Country Reporting: technical update

Background

Country-by-Country Reporting (CbCR) originated as part of the OECD’s Base Erosion and Profit Shifting (BEPS) Action 13 initiative in 2015, aimed at providing tax authorities with standardized data on (a.o.) profits, revenues, taxes paid, employees, and tangible assets broken down by country, to help detect profit-shifting and tax avoidance. Historically, these reports were confidential, exchanged only among tax administrations.

Public Country-by-Country Reporting (public CbCR) was introduced at EU level as part of a broader push to enhance corporate transparency and public accountability, particularly in response to concerns about aggressive tax planning by large multinational groups (with global revenues exceeding €750 million and operations in the EU). The EU Public CbCR Directive requires in-scope multinational enterprises to publicly disclose selected financial and tax information on an annual basis, with the report to be published within 12 months after the end of the relevant financial year. The rules apply to financial years starting on or after 22 June 2024, meaning that, for groups with a calendar-year financial year, the first public CbCR will relate to the 2025 financial year and must be made publicly available by 31 December 2026.

Public CbCR, unlike OECD CbCR, is not a tax reporting obligation but a corporate transparency requirement embedded in accounting law. Its legal basis sits within company and accounting legislation – in Belgium, the Belgian Code of Companies and Associations (BCCA) – and it is enforced through filing and publication rules similar to those for annual accounts. By contrast, OECD CbCR is a confidential tax compliance obligation grounded in tax legislation – in Belgium, Belgian Income Tax Code 1992 (BITC 1992) – and is reported solely to tax authorities for risk-assessment purposes rather than for public disclosure.

Key technical update

For the publication of annual accounts, the NBB uses XBLR, for which a so-called “taxonomy” is required. An XBRL taxonomy defines the standardised data structure that companies must use when submitting financial or regulatory information in XBRL (eXtensible Business Reporting Language) format. It specifies which data points must be reported, how they are defined, and how they relate to each other, enabling consistent digital reporting and automated analysis.

 iXBRL (Inline XBRL) builds on this concept by embedding XBRL tags directly into a human-readable HTML document. This allows a single report to serve both as a readable set of financial statements for users and as a machine-readable data source for regulators and automated processing systems. iXBRL therefore bridges traditional publication requirements with digital reporting, reducing duplication and enhancing transparency and data usability.

 In December 2025, the EC has launched the pCBCR taxonomy project in 2025 to assist companies in preparing the pCBCR in the common template and the iXBRL (eXtensible Business Reporting Language) format, as required by Directive 2013/34/EU and Implementing Regulation (EU) 2024/2952.

 For entities falling within the scope of pCBCR*, please be informed as follows:

• The core pCBCR taxonomy file has been published by the EC on 22 December 2025. It is structured with all the elements that are needed to be tagged when creating an iXBRL report.
• Starting from January 2026 a new review cycle has been launched to collect feedback from the public and especially the report preparers in order to further improve the taxonomy and the report generator.
• The updated versions of both of them and of the documentation will be published on July 2026.

On 24 December 2025, the NBB informed the public that the new definitive taxonomy, now including the Public CbCR model, is now available on the website of the Central Balance Sheet Office. This update follows the transposition of EU Directive 2021/2101 by the Belgian law of 8 January 2024 and the Royal Decree of 18 June 2024. The NBB has confirmed that submissions in PDF format are not permitted.

• European entities must file in iXBRL (Inline XBRL). (It is noted that temporary XBRL is allowed only if the final iXBRL taxonomy from the EC is not ready by the end of 2025 or early 2026. It is not entirely clear whether the publication by the EC on 22 December 2025 should be regarded as final, considering the review cycle that has been launched to collect feedback from the public.)
• Non-European entities can still use XBRL, insofar as they do not wish to use the EC’s iXBRL taxonomy.

*As a reminder, Public CbCR obligations generally apply to Ultimate Parent Entities or Standalone undertakings with (consolidated) revenues exceeding EUR 750 million in each of the last two consecutive financial years, as well as certain EU subsidiaries or branches of non-EU groups meeting these thresholds.

How we can help

Forvis Mazars can guide you through the entire pCBCR process and support your organization with:

• Preparation of the CbCR, including the transformation of existing CbCR data into the Public CbCR reporting model.
• Converting the Public CbCR data into the mandatory iXBRL format, ensuring the file is technically compliant and ready for submission.
• Verifying consistency between Public CbCR data and the Master File or other transfer pricing documentation, to ensure accuracy prior to public disclosure.